Digital Marketing

What Is Open Rate?

Open Rate Definition

The percentage of email recipients who open a given email, used as a key metric for email marketing campaign performance.

Open Rate: Why It Matters

Open rate indicates whether your subject lines are compelling enough to earn attention in a crowded inbox. A declining open rate is an early warning sign of list fatigue, deliverability problems, or a growing mismatch between subscriber expectations and your actual content.

Open Rate: How It Works

Open rate is tracked via a tiny pixel image embedded in the email, when the image loads, the open is recorded. Since Apple's Mail Privacy Protection (MPP) launched in 2021, this metric has become less reliable for iOS users, as Apple's system pre-loads images regardless of whether the email was actually opened. Click rate is now considered a more reliable engagement signal.

Real-World Example

A marketing agency notices their open rate drops from 28% to 18% over three months. Investigation reveals a large proportion of inactive subscribers dragging down the average. After removing contacts who have not engaged in six months, average open rates recover to 31%.

Quick Facts

Average open rates vary significantly by industry: B2B averages ~21%, e-commerce ~15%
Personalising the subject line with the recipient's first name can increase open rate by up to 26%
Tuesday and Thursday mornings typically achieve the highest open rates across most industries
Apple MPP (2021) inflates open rate figures for iOS 15+ users: use click rate as a supplementary metric